A number of techniques exist for controlling one or more luminaires illuminating a building or other environment, e.g. in order to switch the lights on and off, dim the light level up and down, set a color setting of the emitted light, or request status information from a lighting device.
One technique is to use an application running on a user terminal such as a smartphone, tablet, or laptop or desktop computer. A wired or wireless communication channel is provided between the user terminal and a control unit of the lighting device(s), typically an RF channel such as a Wi-Fi, ZigBee or Bluetooth channel in the case of a mobile user terminal. The application is configured to use this channel to send lighting control requests to the control unit, based on user inputs entered into the application running on the user terminal. In order to determine which luminaire or luminaires are to be controlled, the user selects the desired luminaire(s) from a list presented by the application.
In another example, the application is able to use an inbuilt camera of the user terminal (e.g. rear-facing smartphone camera) to detect coded light signals embedded into the light emitted by the luminaires (i.e. modulated into the light at a frequency high enough to be substantially imperceptible to humans). Based on this technology, each of the luminaires in the system in question is arranged to emit light embedded with a different respective ID (e.g. different code or modulation frequency) that is unique within the system. The user can then point the camera towards the luminaire(s) or scene he or she wishes to control, and the application automatically determines the identity of the relevant luminaires based on the embedded IDs detected in light captured by the camera.
Another technique is to provide an indoor location network to detect when the user is present in a particular zone, e.g. in a particular room. An indoor location network involves a plurality of anchor nodes being installed at various locations throughout the building, each of which (in a device centric approach) emits a beacon signal to be detected by the user's mobile user terminal, or (in a network centric approach) listens for a beacon signal emitted by the mobile terminal. Measurements of these signals such as the received signal strength (e.g. RSSI) or time of flight (ToF) can then be used to determine a current location of the user. When the user performs a user input to control the lights, e.g. to turn on or dim the lights, then the system only controls those luminaires in the room or zone where that user is detected.
Other techniques provide systems for automatically controlling the lights in a building, i.e. rather than requiring an explicit user input from the user. These involve detecting the presence of a user by means of a presence infrastructure or location network, and then automatically turning on or dimming up the lights in any zone where a user is detected to be present, and automatically turning off or dimming down the lights in any zone where a user is not detected to be present. For instance a presence sensor such as a passive infrared (PIR) sensor or active ultrasound sensor may be installed in each room of a building in order to detect whether a user is present in that room, and the luminaires in the respective room may be automatically triggered whenever user presence is detected, timing out after no presence is detected for a certain period.